by Click “Materials Science and Engineering” above to quickly focus on the service reliability of key components of high-speed trains on the comprehensive, comprehensive and professional WeChat platform of materials.
The service reliability of key components of high-speed trains is one of the core factors restricting the development of high-speed trains.
Fatigue life prediction and performance optimization of key components of high-speed trains are key issues that need to be solved urgently.
However, the optimization of fatigue performance of materials mostly depends on “trial and error”, which is not only time-consuming and laborious, but also difficult to ensure the optimization effect.
Although there are many kinds of fatigue life prediction software, there is still a lack of similar commercial software in China.
At the same time, the service safety evaluation of key components of high-speed trains in China lacks the theoretical support of material fatigue performance prediction and optimization, and the relevant international standards are complex, so the evaluation method is difficult to be quickly popularized in enterprises.
The performance data and related parameters are obtained from foreign materials and process conditions, which causes the problem of “acclimatization” in China.
Zhang Zhefeng, a researcher in the Institute of Metals, Chinese Academy of Sciences, led the material fatigue and fracture research team to develop a series of original fatigue theoretical models through years of efforts, which provides a key theoretical support for solving the above problems.
Recently, the researcher Zhang Peng and associate researcher Bai Xin of the team cooperated with the National Engineering Laboratory for High speed Train System Integration of CRRC Changchun Railway Vehicles Co., Ltd.
to combine these original theoretical models with traditional theories for high-speed train bogie and other key component materials, jointly launch the “Fatigue Analysis Platform for Common Materials and Welding Structures of Railway Vehicles”, and have completed all software debugging and acceptance.
The functions of this platform are in line with the development requirements of materials and welding structures for domestic high-speed trains, and have been supported and recognized by CRRC Changchun Railway Vehicles.
The team’s doctors Liu Rui and Wang Bin, associate researchers Zhang Zhenjun and Pang Jianchao, and researcher Zhang Peng proposed a series of theoretical models for prediction and optimization of fatigue performance for low cycle fatigue life, fatigue strength, and fatigue crack growth rate.
As the key theory to solve the problem that material fatigue performance mostly depends on “trial and error”, they were integrated into the fatigue analysis software for the first time.
In terms of low cycle fatigue life, a low cycle fatigue life prediction model based on hysteresis energy parameters is proposed, the relationship between low cycle fatigue life of metal materials and micro damage mechanism is established, and the quantitative prediction of low cycle fatigue life is realized according to important parameters such as tensile static toughness and work hardening rate; In terms of fatigue strength, based on a large number of fatigue strength experimental results and previous data, a prediction model of high cycle fatigue strength is proposed.
By introducing alloy composition, microstructure, macro defects and other parameters, the quantitative prediction and optimization of high cycle fatigue strength of metal materials are realized; In terms of fatigue crack growth rate, through a large number of fatigue crack growth experiments and theoretical analysis of fracture mechanics, on the basis of classical Paris formula, a prediction model of fatigue crack growth rate is proposed by introducing strength factor and toughness factor, and the fatigue crack growth life is rapidly predicted and improved through the graphic method of equal fatigue crack growth rate line.
In addition, the platform also integrates the relationship between strength and hardness, the relationship between fracture toughness and strength, the size effect model of fracture toughness, the equivalent fatigue life method (EQ) and the Monte Carlo probabilistic fatigue strength method (MS) proposed by team members, providing new theories and methods for simplifying relevant performance testing and analysis.
These original research achievements have published more than 10 papers in ActaMaterialia, PhysicalReview B, Journal of MaterialsScience&Technology, MaterialsScience and Engineering: A, International Journal of Fatigue and other journals, and applied for more than 10 patents.
The research work has been supported by key programs of the National Natural Science Foundation of China, joint automobile fund programs, general programs, national key research and development plans, and strategic leading science and technology projects of the Chinese Academy of Sciences.
On the basis of the innovation of fatigue theory, Bai Xin, the associate researcher of the team, integrated the commercial fatigue life analysis software method, established the organization and performance database based on domestic materials and welded joints, solved the problem of differences in methods and parameters between commercial fatigue analysis software and domestic materials/welded joints fatigue analysis methods in average stress correction, structural stress correction, and fatigue strength correction, and integrated the corresponding classical correction theory, The component life prediction module of the software platform is established.
Aiming at the problems that the evaluation standards for welded joints and base materials used in the design of high-speed trains in China involve many aspects, such as complex use and high learning costs, the algorithm integrates ISO12107, Eurocode3, Eurocode9, BS7608, BS7910, DVS1608, DVS1612, IIW, prEN17149, FKM and other common standards for welded joints and base materials of high-speed trains, so that designers can directly call the program modules of relevant standards for calculation, The evaluation process of welding joints and base metal of high-speed train is simplified, which provides convenience for reliability design of key components of high-speed train.
At present, the platform has been installed and operated in CRRC Changchun Railway Vehicles Co., Ltd.
The two sides will continue to carry out in-depth and comprehensive cooperation to further improve the software platform to better serve the service performance evaluation of key components of high-speed trains in view of the shortcomings of traditional theories.
Through development, the software platform is expected to be further promoted and applied to key components in important fields such as aviation, shipbuilding, machinery manufacturing, etc.
The main modules and features of the fatigue analysis platform for common materials and welded structures of railway passenger cars This paper is from the Institute of Metals, Chinese Academy of Sciences..
